21218253168 has 40 divisors (see below), whose sum is σ = 62644367488. Its totient is φ = 6062357952.

The previous prime is 21218253167. The next prime is 21218253169. The reversal of 21218253168 is 86135281212.

It is an interprime number because it is at equal distance from previous prime (21218253167) and next prime (21218253169).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21218253167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31574446 + ... + 31575117.

Almost surely, 2^21218253168 is an apocalyptic number.

21218253168 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21218253168 is an abundant number, since it is smaller than the sum of its proper divisors (41426114320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21218253168 is a wasteful number, since it uses less digits than its factorization.

21218253168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63149581 (or 63149575 counting only the distinct ones).

The product of its digits is 46080, while the sum is 39.

The spelling of 21218253168 in words is "twenty-one billion, two hundred eighteen million, two hundred fifty-three thousand, one hundred sixty-eight".